A New Approach: Ethyl Formate Fumigation to Control Bemisia tabaci (Hemiptera: Aleyrodidae) in a Yellow Melon Vinyl House

Round 1

Reviewer 1 Report

The work is written in a clear, well detailed way and with significant research ideas on the subject. The scientific planning scheme appears pertinent and exhaustive. I have no particular comments or detailed reviews to make on the work, as based on what I have read, it seems to me to be sufficiently complete. I have only one question to ask about how to check the health of those who made the various fumigant treatments during the various tests: how was it evaluated? Were there any specific checks?

Thanks

Author Response

Reviewer 1.

 

The work is written in a clear, well detailed way and with significant research ideas on the subject. The scientific planning scheme appears pertinent and exhaustive. I have no particular comments or detailed reviews to make on the work, as based on what I have read, it seems to me to be sufficiently complete. I have only one question to ask about how to check the health of those who made the various fumigant treatments during the various tests: how was it evaluated? Were there any specific checks?

Thanks

(Answer)

Thank you for your question. We have developed a spray instrument for fumigating ethyl formate into a vinyl mulching house through a nozzle. Ethyl formate is liquidate, needing to be fumed to control insect pests. Therefore, no one is exposed to ethyl formate gas during the experiment.

Author Response File: Author Response.docx

Reviewer 2 Report

Abbreviations must not used in the abstract  In Table 2, why chlorophyll content was checked in the flowering and fruiting parts of the plant Better to use mg/L instead of ppm.  How the temperature was maintained in the room?  Make a list of comparison for the current data with the previous findings. Improve discussion section with more related work. Conclusion section is missing. Kindly provide that.

Author Response

Reviewer 2

 

1. Abbreviations must not used in the abstract 

• All scientific names have been renamed to Bemisia tabaci in Abstract section.

 

 

2. In Table 2, why chlorophyll content was checked in the flowering and fruiting parts of the plant Better to use mg/L instead of ppm. 

(Answer)

Thank you for your comment on it. We determined the phytotoxicity level with chlorophyll contents with different stages of yellow melon. We used leaves of each growth stages. Please, confirm it.

 

We changed the unit according to your suggestion in Table 4 as below

 

Table 4. Assessment of stand-by safety of ethyl formate levels^* (mg/L) at entrance and exit gates of the vinyl house during 1 h ventilation after 2 and 4 h fumigations

Time after ventilation (min)	2 h fumigation		4 h fumigation
	Entrance	Exit	Entrance	Exit
0	0.530 ± 0.053	0.407 ± 0.030	< 0.033	< 0.033
5	0.218 ± 0.026	0.242 ± 0.020	< 0.033	< 0.033
10	0.086 ± 0.009	0.119 ± 0.007	< 0.033	< 0.033
20	< 0.033	< 0.033	< 0.033	< 0.033
30	< 0.033	< 0.033	< 0.033	< 0.033
60	< 0.033	< 0.033	< 0.033	< 0.033

*: EF TLV : < 100 ppm

 

 

 

3. How the temperature was maintained in the room? 

• It was confirmed that the breeding room temperature was maintained with a hot/cold fan and maintained daily through a data logger.

 

4. Make a list of comparison for the current data with the previous findings.

• Thank you for your comment on this issue. However, as we showed our previous work as listed in Reference 35, only one EF studies were undertaken until now. Therefore, we can not make a comparison with previous studies. As we mentioned, it was first work to use ethyl formate in controlling insect pests in agricultural industry, not in quarantine purposes in the world. Please, consider it.

5. Improve discussion section with more related work.

• Thank you for your comment. We improved the discussion section as we added more detailed information from our previous work listed 35 in the reference section as below. Before adding new sentences, we revised this paragraph with new sentences in line 384.

“In addition, the cucumber, also known as the Cucurbitaceae crop, showed no weakness in ethyl formate. A previous study confirmed the insecticidal rate of tobacco powder by more than 90%. However, for eggplant, crop peppers, and tomatoes, there were symptoms due to the sensitive effect on temperature and humidity [35].”

 

It is revised paragraphs.

 

“In a previous study reported by Jeong et al. (2020) [35], ethyl formate did not show any phytotoxicity when they performed fumigation study using a small chamber of 0.275 m³. They also determined phytotoxicities on other agricultural crops such as eggplant, crop peppers, and tomatoes under treatment of ethyl formate with two different exposure times as 2 and 4 hours and complete control conditions on B. tabaci adults with 2.0 g EF/m³ and 1.5 g EF/m³, respectively [35]. In this report, authors found that temperature and humidity conditions induced differently phytotoxicities according to plant species when ethyl formate was applied [35].” 

 

6. Conclusion section is missing. Kindly provide that.

(Answer)

We newly added a Conclusion section as below. Please, find it.

 

“It was necessary to develop new, proper strategies for controlling insect pests in agricultural facilities due to a dramatic increase of insecticide resistance in major insect pests, toxicological issue to workers, and residual properties of pesticides in crops. With this regard, we studied a new application of ethyl formate, a safe fumigant, to control B. tabaci, which has damaged severely to yellow melon (YM) in vinyl house. The LCT₉₀ values of 2, 4 and 12 h EF fumigation against B. tabaci were 1.67, 2.08 and 7.65 g h m⁻³, respectively. As for the LCT₉₀ values of B. tabaci by fumigation times on YM, 2 and 4 h EF fumigation treatments had no phytotoxic effects on YM. Based on these results, high efficacy of ethyl formate was found to control B. tabaci adults and no phytotoxic effects on YM in a vinyl house. Therefore, EF fumigation for 2 h with 2 g m⁻³ concentration level could control over 90% against B. tabaci with no phytotoxic effects on YM. It  would be a new alternative tool for the currently used pesticides.”

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

From the drafting perspective and the contents of the MS, after revision it looks well.